Condenser for refrigerating machine

ABSTRACT

This invention provides a condenser for a refrigerating machine which can improve the condensation characteristics by eliminating the accumulation of the condensed refrigerant in the condenser vessel. The condenser comprising the vessel  14  and a group of heat exchanger tubes  15  disposed in the vessel is used for condensing and liquefying the gaseous refrigerant by heat exchange between the gaseous refrigerant and cooling water circulating in the heat exchanger tubes. The condenser is constituted such that accumulated liquefied refrigerant is removed by forming one or a plurality of spaces in the area wherein the heat exchanger tubes are disposed.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a condenser for a refrigeratingmachine, which is used for condensing and liquefying a gaseousrefrigerant after heat exchange between the gaseous refrigerant andcooling water.

[0003] 2. Description of the Related Art

[0004] In a large scale structure such as a building, for example, theinside space of the building is cooled by circulating cooled water inpipes installed in the building for heat exchange between the cooledwater and the air in the building.

[0005]FIG. 7 shows an example of a condenser included in a refrigeratingmachine. As shown in FIG. 7, this condenser comprises a cylindricalvessel 1 in which a bundle of a plurality of heat exchanger tubes 2 isarranged in a staggered manner.

[0006] There are two groups of heat exchanger tubes 2, one of whichcomprises the forward side (first passing group or first group) tubes,communicated with a cooling water inlet 3, and the other of whichcomprises backward side (second passing group or second group) tubes,communicated with a cooling water outlet 4. The forward side heatexchanger tubes are arranged to be located lower in the vessel, and thebackward side heat exchanger tubes are arranged to be located higher inthe vessel. Cooling water supplied from the cooling water inlet 3 passesthrough the forward side heat exchanger tubes and reaches to a waterchamber (not shown), and then the cooling water returns through thebackward side heat exchanger tubes from the water chamber to bedischarged from the cooling water outlet 4. In this circulation process,the gaseous refrigerant introduced into the vessel 1 by a compressor(not shown) is cooled, condensed and liquefied through the heat exchangewith the cooling water. Note that the liquefied refrigerant is suppliedto an evaporator (not shown).

[0007] However, a problem arises in that, since the heat exchanger tubesare arranged densely in the above-described condenser, the condensedliquid refrigerant moves towards the right and left sides of the vesselalong the heat exchanger tubes by the supply pressure of the gaseousrefrigerant introduced into the vessel and the condensed liquid oftenaccumulates in both the right and left end portions of the foreward sideheat exchanger tubes located lower in of the vessel. When the condensedliquid is accumulated around the second group of heat exchanger tubes,the thick condensed liquid layer accumulated around the heat exchangertubes causes an increase in the heat resistance of the tubes and causesdegradation of the condensation performance of the condenser.

SUMMARY OF THE INVENTION

[0008] The present invention has an object of suppressing accumulationor concentration of the condensed liquid around the heat exchanger tubesand to provide a condenser for the refrigerating machine having improvedcondensation performance.

[0009] The present invention provides a condenser for a refrigeratingmachine which comprises a vessel into which a gaseous refrigerant isintroduced and a bundle of heat exchanger tubes disposed in said vesselfor condensing and liquefying a gaseous refrigerant by heat exchangebetween said gaseous refrigerant and cooling water circulating in theheat exchanger tubes, wherein one or a plurality of vacant spaces areformed with a vertical orientation in the area in which the heatexchanger tubes are disposed, in order to prevent the liquefiedrefrigerant from accumulating around the second group of heat exchangertubes and to accelerate the inflow of the gaseous refrigerant.

[0010] In the above condenser for a refrigerating machine, the vacantspace is formed so as to pass through the cross-sectional area in whichsaid heat exchanger tubes are disposed.

[0011] In the above condenser for a refrigerating machine, the vacantspace is formed vertically when viewed in cross-section such that thespace starts from the bottom and reaches an upper portion of the area inwhich the heat exchanger tubes are disposed.

[0012] The present invention provides another type of the condenser fora refrigerating machine which comprises a vessel into which a gaseousrefrigerant is introduced and a group of heat exchanger tubes disposedin said vessel for condensing and liquefying a gaseous refrigerant byheat exchange between said gaseous refrigerant and cooling watercirculating in said heat exchanger tubes, wherein a plurality of porousplates are arranged at the inner peripheral surface of said vessel forguiding said gaseous refrigerant flowing along the inner surface of saidvessel towards said group of heat exchanger tube groups.

[0013] The present invention provides yet another type of condenser fora refrigerating machine which comprises a vessel into which a gaseousrefrigerant is introduced and a group of heat exchanger tubes disposedin said vessel for condensing and liquefying a gaseous refrigerant byheat exchange between said gaseous refrigerant and cooling watercirculating in said heat exchanger tubes, wherein said heat exchangertubes are arranged at equal intervals, and said heat exchanger tubeslocated in the lower part are used for supplying said cooling water andsaid heat exchanger tubes located in the upper part are used fordischarging said cooling water, and the number of heat exchanger tubeslocated in said upper part is less than the number of heat exchangertubes located in said lower part of the vessel by making the area ofsaid upper part smaller than that of said lower part.

[0014] The present invention provides yet another condenser for arefrigerating machine which comprises a vessel into which a gaseousrefrigerant is introduced and a group of heat exchanger tubes disposedin said vessel for condensing and liquefying a gaseous refrigerant byheat exchange between said gaseous refrigerant and cooling watercirculating in said heat exchanger tubes, wherein said heat exchangertubes located in the lower part are used for supplying said coolingwater and said heat exchanger tubes located in the upper part are usedfor discharging said cooling water, and the number of heat exchangertubes located in said upper part is less than the number of heatexchanger tubes located in said lower part of the vessel by setting theinterval between heat exchanger tubes in the upper part to be largerthan the interval between heat exchanger tubes in the lower part.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a cross-sectional diagram showing a schematic structureof a refrigerating machine to which the condenser according to thepresent invention is applied.

[0016]FIG. 2 is a schematic cross-sectional diagram showing the firstembodiment of the present invention.

[0017]FIG. 3 is a schematic cross-sectional diagram showing the secondembodiment of the present invention.

[0018]FIG. 4 is a schematic cross-sectional diagram showing the thirdembodiment of the present invention.

[0019]FIG. 5 is a schematic cross-sectional diagram showing the fourthembodiment of the present invention.

[0020]FIG. 6 is a schematic cross-sectional diagram showing the fifthembodiment of the present invention.

[0021]FIG. 7 is a schematic cross-sectional diagram showing aconventional condenser.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the condensers for the refrigeratingmachine of the present invention will be described.

[0023]FIG. 1 shows a schematic structure of a refrigerating machine.This refrigerating machine comprises a condenser 10 for condensing andliquefying a refrigerant by heat exchange between the cooling water andgaseous refrigerant, an expansion valve 11 for pressure reduction of thecondensed refrigerant, an evaporator 12 for cooling the cooling water byheat exchange between the condensed refrigerant and the cooling water,and a compressor 13 for supplying the refrigerant to the condenser 10after evaporation and vaporization of the refrigerant. Note that thecooled water in the above-described evaporator is used for cooling ofthe building.

[0024]FIG. 2 is a cross-sectional view along the line II-II in FIG. 1. Ashown in FIG. 2, the condenser comprises a cylindrical vessel 14 and aplurality of heat exchanger tubes 15 which are arranged as a bundle inthe vessel 14.

[0025] The heat exchanger tubes are used for the flow of the coolingwater and they are arranged along the longitudinal direction(perpendicular direction to the paper in FIG. 2) of the vessel 14. Thereare two groups of heat exchanger tubes 15, one which is the forward sideor first group heat exchange tubes communicated with the cooling waterinlet 16 and another is the backward side or second group heat exchangertubes communicated with cooling water outlet 16, and the direction ofthe cooling water flow in the forward side tubes 15 differs from that inthe backward side tubes 16.

[0026] As shown in the cross-sectional view of FIG. 2, a vacant space 18is provided in the condenser 10 according to the present embodiment.This vacant space 18 passes vertically across the area wherein the heatexchanger tubes are disposed, and this space 18 separates heat exchangertubes into right and left groups. Note that the above vacant space 18can be formed by extracting the heat exchanger tubes 15 which wereoriginally disposed in the position of the space 18. Thus, this space ishereinafter called an “extracted row”.

[0027] The condensation performance of the condenser according to thepresent embodiment can be improved by preventing the concentration andaccumulation of the condensed liquid (liquid refrigerant) on the heatexchanger tubes disposed at the central portion of the vessel byproviding the extracted row.

[0028] In addition, provision of the extracted row improves thecondensation performance of the condenser by promoting the supply of thegaseous refrigerant between the heat exchanger tube groups 15.

[0029] Although only one extracted row is formed in the above-describedembodiment, two or more extracted rows may be provided by disposing themseparated at constant intervals passing through upper and lower side ofthe vessel (not shown). In such a case, it is preferable to formextracted rows having a width corresponding to one to three lines ofheat exchanger tubes 15 for every 10 lines of heat exchanger tubes.

[0030] Providing a plurality of extracting rows as above makes itpossible to improve the heat transfer performance of the heat exchangertubes by reducing the accumulation of the condensed refrigerant in thevessel and the heat transfer performance is further improved byaccelerating the supply of the gaseous refrigerant.

[0031]FIG. 3 shows a cross-sectional view of another embodiment of thepresent invention in which three extracted rows 19 are formed extendingfrom the bottom to the upper portion of the area wherein the heatexchanger tube group 15 is disposed. As shown in FIG. 3, the extractedrows do not reach the top portion of the area wherein the heat exchangertubes 15, because the condensed refrigerant is not likely to accumulatearound the heat exchanger tubes 15 located upwards of the area whereinthey are disposed because the condensed refrigerant descends to thelower part of the vessel 14 under the effect of gravity.

[0032] Formation of the extracted rows according to the presentembodiment improves the efficiency of the condenser more than enough tooffset the decrease in the heat exchange efficiency due to the reductionof the number of heat exchange tubes.

[0033] On the upper side of the extracted rows 19, it is preferable toleave more than two lines of heat exchanger tubes 15. It is a matter ofcourse that, in this embodiment, each extracted row 19 may be formed byextracting less than three rows or more than three rows of heatexchanger tubes.

[0034]FIG. 4 shows another embodiment of the present invention. Thecondenser 10 according to this embodiment comprises, in addition to theheat exchanger tubes, two porous plates 20 disposed at both the rightand left center portions of the inner surface of the vessel 14 and theporous plates are attached the inner surface of the vessel 14 so as toprotrude horizontally along the longitudinal direction (perpendicular tothe sheet plane of FIG. 4) of the vessel 14.

[0035] According to this embodiment, since a portion of the refrigerantvapor circulating along the inner surface of the vessel 14 is guided andintroduced into the center portion of the vessel 14 by the porousplates, and the introduction of the gaseous refrigerant into the centerportion of the heat exchange tubes assists the effective liquefaction ofthe refrigerant and effective discharge of the liquid refrigerant fromthe vessel, preventing the accumulation of the liquid refrigerant in thevessel. As a result, the accumulation of the condensed liquidrefrigerant in the vessel 14 can be reduced, in other words, thethickness of the liquid layer refrigerant formed on the heat exchangertubes can be reduced, so that the overall heat transfer efficiency ofthe condenser is increased. It should also be noted that theabove-described porous plate can be added to the vessels 14 shown inFIGS. 2 and 3.

[0036]FIG. 5 shows another embodiment of the present invention. In thecondenser 10 according to this embodiment, the number of the heatexchanger tubes belonging to the first passing group located in thelower part of the vessel 14 which are connected to the cooling waterinlet 16, as shown in FIG. 1, is increased, and the number of the heatexchanger tubes belonging to the second passing group tubes, as shown inFIG. 1, located in the upper part of the vessel 14 which are connectedto the cooling water outlet 17 is decreased.

[0037] That is, all of the heat exchange tubes 15 in this embodiment aredisposed at equal pitch and the area for disposing the second group ofheat exchange tubes is smaller than the area for disposing the firstgroup of heat exchange tubes. Thereby, the number of second group heatexchange tubes located above is decreased than the number of the firstgroup heat exchange tubes located below.

[0038] According to the present embodiment, the amount of the condensedliquid formed in the upper part of the area where the tubes are disposedis reduced, so that the amount of condensed liquid falling on the heatexchanger tubes located in the lower part of the area where the tubesare disposed is also reduced.

[0039] Accordingly, the degradation of the heat transfer property of theheat exchange tubes arranged lower of the vessel can be suppressed andthe resulting overall heat transfer property of the condenser isimproved.

[0040]FIG. 6 shows another embodiment of the present invention. In thecondenser 10 according to this embodiment, the number of the secondgroup heat exchanger tubes located in the upper part of the vessel isreduced increasing the interval between the second group heat exchangertubes by 1.1 to 3 times.

[0041] In the condenser 10 according to this embodiment, since thenumber of the second group heat exchanger tubes is reduced, the amountof liquid refrigerant which falls on the exchanger tubes in the lowerside of the vessel is reduced and a decrease in the heat transferperformance of the heat exchanger tubes can be suppressed, which resultsin increasing the overall transfer efficiency of the condenser.

[0042] Note that although the heat exchanger tubes in theabove-described embodiments are disposed in a staggered manner, thepresent invention can also be applied to the vessel in which the heatexchanger tubes are disposed with a lattice-like cross section.

[0043] As described above, according to one condenser for refrigeratingmachines of the present invention, since one or a plurality of spacesare formed in the area where the heat exchanger tubes are disposed, theliquid refrigerant can be prevented from accumulating in theabove-mentioned spaces, which results in improving the condensationperformance of the condenser.

[0044] According to another condenser for the refrigerating machine ofthe present invention, two porous plates are mounted on the innersurface of the condenser vessel for guiding the gaseous refrigerantflowing along the inner surface of the vessel to the central portion ofthe group of heat exchanger tubes. Guiding the gaseous refrigerant tothe central portion of the group of heat exchanger tubes acceleratesliquefaction of the gaseous refrigerant and the discharge of theliquefied refrigerant from the vessel, which results in improving theheat transfer efficiency of the condenser by eliminating theaccumulation of the liquefied refrigerant in the interstices of the heatexchanger tubes.

[0045] According to still another condenser for the refrigeratingmachine of the present invention, the number of the backward side heatexchanger tubes located in the upper part of the vessel is made smallerthan the number of forward side heat exchanger located in the lower partof the vessel. Accordingly, the amount of condensed liquid refrigerantformed by the second group of tubes is reduced, which reduces the amountof the liquid refrigerant which falls onto the forward side heatexchanger tubes, where the heat exchange rate is higher than thebackward side tubes due to the larger temperature difference between therefrigerant gas and the cooling water, which results in improving theheat transfer efficiency of the overall heat exchange tubes.

[0046] Furthermore, according to still another condenser for therefrigerating machine of the present invention, the pitch of thebackward side heat exchange tubes located in the upper part of thevessel is made larger than that of the forward side heat exchange tubeslocated in the lower part of the vessel. Accordingly, the heat transferefficiency can be improved by reducing formation of the liquidrefrigerant in the upper part of the vessel of the liquid refrigerant,which falls onto the heat exchange tubes in the lower part of thevessel.

What is claimed is:
 1. A condenser for a refrigerating machinecomprising: a vessel into which a gaseous refrigerant is introduced; anda group of heat exchanger tubes disposed in said vessel for condensingand liquefying a gaseous refrigerant by heat exchange between saidgaseous refrigerant and cooling water circulating in said heat exchangertubes; wherein, in a cross-sectional view, one or a plurality of vacantspaces are formed with a vertical orientation in an area in which saidheat exchanger tubes are disposed, for preventing the liquefiedrefrigerant from accumulating around said heat exchanger tubes and foraccelerating an inflow of the gaseous refrigerant.
 2. A condenser for arefrigerating machine according to claim 1, wherein said vacant space isformed so as to pass through a cross-sectional area in which said heatexchanger tubes are disposed.
 3. A condenser for a refrigerating machineaccording to claim 1, wherein said vacant space is vertically formed incross-sectional view such that the space starts from the bottom andreaches an upper portion of the area wherein said heat exchanger tubesare disposed.
 4. A condenser for a refrigerating machine comprising: avessel into which a gaseous refrigerant is introduced; and a group ofheat exchanger tubes disposed in said vessel for condensing andliquefying a gaseous refrigerant by heat exchange between said gaseousrefrigerant and cooling water circulating in said heat exchanger tubes;wherein a plurality of porous plates are fitted on the inner peripheralsurface of said vessel for guiding said gaseous refrigerant flowingalong the inner surface of said vessel into said group of heat exchangergroups.
 5. A condenser for a refrigerating machine comprising: a vesselinto which a gaseous refrigerant is introduced; and a group of heatexchanger tubes disposed in said vessel for condensing and liquefying agaseous refrigerant by heat exchange between said gaseous refrigerantand cooling water circulating in said heat exchanger tubes; wherein saidheat exchanger tubes are disposed at an equal interval, and a group ofheat exchanger tubes located in a lower region are used for supplyingsaid cooling water forward and another group of said heat exchangertubes located in an upper region is used for returning said coolingwater backward, and the number of heat exchanger tubes located in saidupper region is made smaller than the number of heat exchanger tubeslocated in said lower region by making the area of said upper regionsmaller than the area of said lower region.
 6. A condenser for arefrigerating machine comprising: a vessel into which a gaseousrefrigerant is introduced; and a group of heat exchanger tubes disposedin said vessel for condensing and liquefying a gaseous refrigerant byheat exchange between said gaseous refrigerant and cooling watercirculating in said heat exchanger tubes; wherein a group of said heatexchanger tubes located in the lower region is used for supplying saidcooling water forward and a group of said heat exchanger tubes locatedin the upper region is used for returning said cooling water backward,and the number of heat exchanger tubes disposed in said upper region ismade smaller than the number of heat exchanger tubes disposed in saidlower region by making an interval between heat exchanger tubes in saidupper region larger than an interval between the heat exchanger tubes insaid lower region.